Thanks. I find that when cold bluing you should evenly heat the part to the point where you can't quite hold on to it, although you shouldn't be actually touching it for skin oil reasons, that's just a WAG temperature reference. Obviously it has to be perfectly clean first, and the heating can't transfer any contaminates. Then use 100% cotton Q-tips or balls to apply the blue. When the whole part is colored, do a second coat that might involve some light scrubbing to get the color even. Then give it a few seconds to work. If it is drying off right away it's a bit too hot. Then thoroughly rinse in cold water. Completely dry it right away. Use more gentle heat and blowing if needed. Finally, generously coat with gun oil.
I don't recall where I read that slight heating helps, but whoever it was, hit that nail.
I wouldn't say you need to cut yours down. We are each making our own grown-up toy inspired by the same source. If a museum needed an exact copy of the original, then that would be different, but we're just having fun challenging ourselves to make a thing.